When no start display time is found in a subpicture then return with an error message. Problem reported by: Hytham Alihassan.

Update freetype from 2.1.9 to 2.3.0. This has been tested on veda, espilon, altair, altair/sid-id386/Mingw32.

* download the SDL stuff from sourceforge instead of the bogus official server, as the SF park is much faster and more reliable (forward-porting [18622])

ts.c, telx.c: Fallback to teletext detection if TS detection wasn't possible

   for different languages. Slightly changed the way the dvbsub parser
   works to allow correct streaming with --sout-all or --programs.
 * modules/mux/mpeg/ts.c: Changes to allow descriptor pass-through with
   telx and dvbsub. This is kind of kludgy.
 * module/codec/telx.c: Got rid of the ugly static variables and use 
   info from the TS demux.

- the stream provided by thedj containing some kind of VPS informations know works fine (they aren't displayed as subtitles anymore). It also solve the same issue on two examples streams on the vlc file repository (called stream-demux-telx-1.dump and stream-demux-telx-2.dump)

- got rid of a kludge that used to be necessary on the "has-subtitles.ts" example stream to avoid subtitles disapearing too fast in some cases. I don't know exactly why it's not anymore necessary, probably because I handle better the subtitle flag now.

- now the page number is handled independently for each 8 magazines

   Vincent Penne.

Remove useless test i_chunk is uint32_t and cannot be lower then zero. This fixes a compile warninig and hopefully doesn't introduce an mp4 problem. Test your mp4's.

Revert part of rev 18553 where p_track->i_chunk test has changed. It shouldn't have gone in this commit.

 - out of bound read initially uncovered by sam,
 - also malloc() can really return NULL for arbitrary large alloc,
   return value MUST be checked.